On Wed, 14 Feb 2007, Matthias Andree wrote:
[...] The other important concern for a portable software as dovecot is portability. On some systems, temporary failure of getpwnam() is indistinguishable from permanent failure, thus the only solution to this approach is Postfix's: implement a NIS lookup client to access the password database to circumvent the many libc bugs lurking there. [...]
That sort of supports my suggestion for an option, default off and which a site-admin would have to be explicit in turning on, to mark 'deliver' failures as EX_TEMPFAIL.
We have had a source code hack since October (in "deliver.c", simply replacing a "return ret" occurence with "return EX_TEMPFAIL") and it has worked nicely (ported forward from rc8 towards rc22). Mail re-queues and a later delivery attempt then succeeds.
And lingers around in the queue for a week if an account has been terminated? Doesn't look like a 'solution' to me.
(I hope that I never used the word 'solution' to describe it! But it is a workaround various real bugs in various real systems, which have had no real resolution despite some real-long timescales.)
This EX_TEMPFAIL would be an option, default off. If a site-admin explicitly, consciously, opted into this changed behaviour, that possible queue build up would, indeed be a factor to consider for such a (non-default) choice. For some sites, this might well be preferable to discarding valid email. Suppose, for instance, that rejecting valid email adversely reflected of the company's reputation and resulted in lost customers. Such a site would, one hopes, be monitoring its queues anyway for abnonmally long residencies.
(An aside, interacting with another thread: Don't let this relatively minor suggestion delay the formalising of official version 1.0!)
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